Creating Differentiated Therapies to Improve the Lives of Cancer Patients

January 2021 Forward-Looking Statements and Disclaimer

Zentalis Pharmaceuticals, Inc. (“we,” “us,” “our,” “Zentalis” or the “Company”) cautions that this presentation (including oral commentary that accompanies this presentation) contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this presentation that do not relate to matters of historical fact should be considered forward-looking statements, including without limitation statements regarding our future financial or business performance, plans, prospects, trends or strategies, objectives of management, competition and other financial and business matters; the potential, safety, efficacy, and regulatory and clinical progress of our current and prospective product candidates, planned clinical trials and preclinical activities, and projected research and development costs; our current and prospective collaborations; the estimated size of the market for our product candidates; and the timing and success of our development and commercialization of our anticipated product candidates and the market acceptance thereof are forward-looking statements, as well as statements that include the words “expect,” “intend,” “plan,” “believe,” “project,” “forecast,” “estimate,” “may,” “should,” “anticipate” and similar statements of a future or forward-looking nature. These statements are neither promises nor guarantees, but involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements, including, but not limited to, the following: the outbreak of the novel coronavirus disease, COVID-19, has adversely impacted and may continue to adversely impact our business, including our preclinical studies and clinical trials; our limited operating history, which may make it difficult to evaluate our current business and predict our future success and viability; we have and expect to continue to incur significant losses; our need for additional funding, which may not be available; our substantial dependence on the success of our lead product candidate; failure to identify additional product candidates and develop or commercialize marketable products; the early stage of our development efforts; potential unforeseen events during clinical trials could cause delays or other adverse consequences; risks relating to the regulatory approval process or ongoing regulatory obligations; failure to obtain U.S. or international marketing approval; our product candidates may cause serious adverse side effects; inability to maintain our collaborations, or the failure of these collaborations; our reliance on third parties; effects of significant competition; the possibility of system failures or security breaches; risks relating to intellectual property; our ability to attract, retain and motivate qualified personnel; and significant costs as a result of operating as a public company. These and other important factors discussed under the caption “Risk Factors” in our Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2020 filed with the U.S. Securities and Exchange Commission (SEC) and our other filings with the SEC could cause actual results to differ materially from those indicated by the forward-looking statements made in this presentation. Any such forward-looking statements represent management’s estimates as of the date of this presentation. New risks and uncertainties may emerge from time to time, and it is not possible to predict all risks and uncertainties. While we may elect to update these forward-looking statements at some point in the future, we assume no obligation to update or revise any forward-looking statements except to the extent required by applicable law. Although we believe the expectations reflected in such forward-looking statements are reasonable, we can give no assurance that such expectations will prove to be correct. Accordingly, readers are cautioned not to place undue reliance on these forward-looking statements. No representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements.

This presentation also contains estimates and other statistical data made by independent parties and by us relating to market size and other data about our industry. This data involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such data and estimates. In addition, projections, assumptions and estimates of our future performance and the future performance of the markets in which we operate are necessarily subject to a high degree of uncertainty and risk. Neither we nor our affiliates, advisors or representatives makes any representation as to the accuracy or completeness of that data or undertake to update such data after the date of this presentation.

Data of Fulvestrant, RAD1901, Abemaciclib, Alpelisib, AZD1775, Venetoclax and Osimertinib presented in this presentation is based on evaluation of comparable proxy chemical compounds purchased from commercial sources rather than the pharmaceutical company commercializing or developing, as applicable, the compound.

2 Zentalis Overview

Integrated Discovery Engine has produced 4 FDA-cleared 1 INDs in 5 years

Our Mission: Potentially differentiated lead programs: oral SERD for 2 breast cancer (ZN-c5) and WEE1 for solid tumors (ZN-c3) Discover and Develop Revolutionary Medicines to 3 Additional pipeline programs targeting fundamental cancer pathways: BCL-2 (ZN-d5) and EGFR (ZN-e4) Improve the Lives of Patients Globally Potential for internal and third-party combination 4 strategies across portfolio

Experienced management, seasoned SAB, leading life 5 sciences investors and large cap pharma partners

3 Zentalis Leadership

Experienced Management Team

Anthony Sun, M.D., MBA Peter Huang, Ph.D. Chairman and Chief Executive Officer Senior Vice President, Discovery Research Ahmed Samatar, Ph.D. Kevin Bunker, Ph.D. Senior Vice President, Oncology Research Chief Operating Officer Dimitris Voliotis, M.D. Senior Vice President, Clinical Development Melissa Epperly, MBA Chief Financial Officer Orna Bornstein, Ph.D. Vice President, Clinical Operations Cam Gallagher, MBA Executive Director Robert DiVasto, P.E. Vice President, Manufacturing and Supply

Alexis Pinto, J.D. Meena Rao, Ph.D. Chief Legal Officer Vice President, Regulatory Affairs

4 Zentalis Advisory Boards

Scientific Advisory Board Mayo Clinic Advisory Board

Anthony Letai, M.D., Ph.D. Stephen Ansell, M.D., Ph.D.

Ross Levine, M.D. Andrew Badley, M.D.

Donald McDonnell, Ph.D. Shaji Kumar, M.D.

Kwok-Kin Wong, M.D., Ph.D.

5 Highly Efficient ‘Integrated Discovery Engine’ Cleared four INDs in five years and expect to file fifth IND in 2021

1 3

IDENTIFY fundamental CREATE proprietary NCEs biological pathways CANCER MEDICINAL designed to address of cancers BIOLOGY CHEMISTRY observed limitations

2 4

ANALYZE key compounds GENERATE strong preclinical targeting these pathways and NEW TECHNOLOGIES evidence to support assess their limitations + Genomic potentially differentiated Discovery development profiles Platform

6 Broad Oncology Pipeline Designed to Improve Patient Outcomes

IND Enabling Phase 1/2 Phase 3 Collaborator (1) ZN-c5: Oral SERD Monotherapy Breast Cancer Combinations

ZN-c3: WEE1 Inhibitor Monotherapy Solid Tumors Combinations

ZN-d5: BCL-2 Inhibitor AML or Non-Hodgkin’s Lymphoma Monotherapy Breast Cancer Combination with ZN-c5

ZN-e4: EGFR NSCLC

(1) Zentalis is currently evaluating ZN-c5 in combination with palbociclib (Ibrance), as part of a clinical research collaboration with Pfizer, and intends to evaluate ZN-c5 in combination with abemaciclib (Verzenio), as part of a clinical research collaboration with Lilly. Zentalis maintains full ownership of ZN-c5 in each such collaboration. SciClone has development and commercial rights to ZN-e4 in Greater China (including Macau and Hong Kong), South Korea, Taiwan and Vietnam. Zentera, our majority-owned joint venture, has development and commercial rights to ZN-c5, ZN-c3 and ZN-d5 in select Asian countries (including China). Zentera intends to submit an IND in China for each 7 of ZN-c5, ZN-c3 and ZN-d5 in 2021. Progress Since Our IPO and Follow-on Use of Proceeds

Recent Trial Initiations 2021 Milestones

Multiple Clinical Milestones Achieved: ➢ ZN-c5: ✓ ZN-c5: • Initiate Phase 1b combination study with ZN-d5 • 40% Clinical Benefit Rate (CBR) from • Initiate Phase 2/3 monotherapy study in earlier-stage monotherapy dose escalation study patients • 4Q 2020: Initiated Phase 1b combination ➢ ZN-c3: study with abemaciclib in collaboration with • Initiate Phase 1 combination trial with PARP inhibitors Eli Lilly in ovarian cancer ✓ ZN-c3: • Initiate Phase 2 monotherapy trial for uterine serous • Promising initial pharmacokinetic and safety carcinoma (USC) data ➢ ZN-d5: • 4Q 2020: Initiated Phase 1 combination study with chemotherapy in ovarian cancer • Initiate Phase 1b combination study with ZN-c5 ✓ ZN-d5: ➢ ZN-e4: • 4Q 2020: Initiated a Phase 1 monotherapy • Initial results from dose escalation study study in AML and Non-Hodgkin’s Lymphoma

8 ZN-c5: Oral SERD

9 ZN-c5: Oral SERD Candidate for ER+/HER2- Breast Cancer

1 2 3 IDENTIFY: SERD ANALYZE: Fulvestrant CREATE: ZN-c5 • Clinically validated approach • Fulvestrant limitations: • ZN-c5 designed as an oral SERD to have: • Potential use as backbone − 2 painful 5mL monthly − High potency and selectivity therapy intramuscular injections − Improved solubility (insoluble) • Fulvestrant: only FDA-approved − Compelling PK (long half life) SERD − Capped efficacy at FDA- − Favorable safety and − First and second-line approved dose based on tolerability treatment as monotherapy clinical and preclinical data − No agonist activity and in combination with − Low convenience and high CDK4/6 or PI3Kα inhibitors • Goal: safely establish increased resource utilization drug exposure to enhance efficacy

Current Status: Phase 1/2 Trial (Monotherapy Dose Escalation & Expansion and Dose Escalation in Combination with Palbociclib) and Phase 1b Combination with Abemaciclib with Eli Lilly

10 Vast Market Opportunity for Oral SERDs

~$1Bn+ Markets in Various Classes Treating ER+ Breast Cancer (1)

$14.4Bn

$1.0Bn $1.4Bn $0.8Bn

Fulvestrant - AstraZeneca (SERD) CDK4/6 Inhibitors PI3K Inhibitors mTOR Inhibitors

Faslodex Sales of ~$1.0Bn Reflect Only Part of Significant Market Potential for an Oral SERD and Only Approved for Metastatic Patients (1) Highest projected or historical sales for currently marketed products in breast cancer; includes historical years for drug classes with generic competition; based on data from EvaluatePharma as of July 2020 11 ZN-c5: Demonstrated Strong Preclinical Anti-Tumor Activity

ZN-c5 exhibited dose proportional response as well as meaningful tumor shrinkage in combination with palbociclib

Breast Cancer Model (MCF7) Breast Cancer Model (MCF7), Mean ± SE

Combination of Palbociclib 50 mg/kg + ZN-c5 30 mg/kg VehicleVehicle 800 FulvestrantFulvestrant (200 (200 mg/kg) mg/kg) QW5 qw5(1) 1,000

700 ZNZN-c5-c5 (1 mg/kg) mg/kg) QD 900

) ) ZNZN-c5-c5 (5 mg/kg) mg/kg) QD 3 3 800 600 ZN-c5 (40 mg/kg) ZN-c5 (40 mg/kg) QD 700

(mm Palbociclib (50 mg/kg) 500 Palbociclib (50 mg/kg) QD Palbociclib (50 mg/kg) + 600 ZNPalbociclib-c5 (5 mg/kg) (50 mg/kg) + ZN-c5 400 (5 mg/kg) QD 500 400 Start of 300 treatment 300

200 Tumor Volume Tumor Tumor Volume (mm Volume Tumor 200 100 100 0 0 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 Study Days Study Days

12 (1) Fulvestrant based on evaluation of comparable proxy chemical compounds purchased from commercial sources rather than the pharmaceutical companies commercializing the compound. ZN-c5: Robust Anti-Tumor Activity in Preclinical ESR1 Models as Monotherapy and in Combination with CDK4/6 Inhibitors

ESR1 mutations commonly drive resistance – prevalence ranges from 11% to 39%

ESR1 Mutant Breast Cancer Model (WHIM20) 1,200 Vehicle

1,000

Fulvestrant (5 mg) (1)

) ) 3 800 Abemaciclib (50 mg/kg) QD (1)

(1) 600 Palbociclib (50 mg/kg) QD

ZN-c5 (40 mg/kg) QD

400 Tumor Volume (mm Volume Tumor

ZN-c5 (40 mg/kg) + Abemaciclib (50 200 mg/kg) QD (1) ZN-c5 (40 mg/kg) + Palbociclib (50 (1) 0 mg/kg) QD 0 10 20 30 40 50 60 70 80 90

Days of Treatment

13 (1) Data based on evaluation of comparable proxy chemical compounds purchased from commercial sources rather than the pharmaceutical companies commercializing the compound. ZN-c5: Strong Preclinical Anti-Tumor Activity in Combination with PI3Kα Inhibitor ~1/3 of HR+ breast cancer tumors are resistant to endocrine therapy harbor activating mutations of PIK3CA

800 Tumor Volume (MCF7), Mean ± SE Vehicle

600

) (1)

3 Fulvestrant (3 (3mg/dose) mg/dose) QW4 QW4

Alpelisib (1)(50(50 mg/kg) mg/kg) QD QD 400

ZN-c5 (1 mg/kg) QD Tumor Volume (mm Volume Tumor 200 Fulvestrant (3 mg/dose) QW4 + Alpelisib (50 mg/kg) QD

ZN-c5ZN-c5 (1 mg/kg) QD + AlpelisibAlpelisib (50(1) (50 mg/kg) mg/kg) QD QD 0 0 5 10 15 20 25 Days Post Treatment

14 (1) Data based on evaluation of comparable proxy chemical compound purchased from commercial sources rather than the pharmaceutical company commercializing the compound ZN-c5: Clinical Development Plan

Ongoing and Planned Clinical Programs Overview Phase 1/2 Study (ZN-c5-001) Phase 1b Study • Topline results from Phase 1 monotherapy dose escalation (1) – 40% CBR; Median PFS: 3.8 mo Monotherapy Dose Escalation Median prior therapies: 4 ZN-c5 – No DLTs observed and well tolerated – Study continues enrollment

Monotherapy Expansion Combination Dose Escalation Combination Dose Escalation ZN-c5 (2) ZN-c5 + palbociclib (2) ZN-c5 + abemaciclib • Window of Opportunity study initiated in 1Q 2020 to analyze Enrolling Enrolling Initiated 4Q 2020 levels of tumor ER degradation (8 patients enrolled)

• 2021: Intend to initiate Phase 1b Monotherapy Phase 2 Combination Phase 2 combination trial with ZN-d5 & ZN-c5 ZN-c5 + palbociclib Phase 2/3 trial in earlier-stage Expected initiation 1H 2021 Expected initiation 1H 2021 breast cancer

(1) As of June 30, 2020, we have enrolled 15 patients in the Phase 1, monotherapy dose escalation portion of this trial, three patients each at the dose levels of 50 mg, 75 mg, 100 mg, 150 mg and 300 mg. (2) As of June 30, 2020, 14 patients were enrolled in the Phase 1, monotherapy expansion portion of this trial, 12 patients at the 150 mg dose and two patients at the 300 mg dose. Of these 14 patients, five are still on treatment and nine discontinued due to disease progression. As of June 30, 2020, we have enrolled 15 patients in the Phase 1, combination dose escalation portion of this trial. Of 15 these 15 patients, nine are still on treatment and six discontinued due to disease progression (n = 5) and physician decision (n = 1). ZN-c5: Initial Topline Results from Monotherapy Dose Escalation Treatment Duration (months) and Response by Dose as of June 30, 2020

XXX Best Response: PR/SD/PD (2) (1) CBR: 6/15 (40%) (1) XXX PFS median: 3.8 mos [95%CI: 1.6, 6.3]

XXX

Hormonal Mutation Prior based Prior Chemo Prior CDK4/6 Prior Fulvestrant ESR1 ESR1 Median Prior Trx for Adv Dx: 4 (2, 8) U 5 1061 -015 (300P MG : NM)Y SD

+ 2 1061 -016 (300P MG : M)- SD 300 mg

U 2 1070 -017 (300P MG : M)Y SD - 2 1061 -014 (150P MG : NM)- SD 150 mg + 2 1021 -016 (150MGP : NM)Y SD - 2 1040 -015P, (150 R (E) MG : M)Y PD

+ 3 1061 -009 (100P MG : M)Y SD 100 mg +104-011 (1004 MG : M)XXXXXXXXXXXXXXXX1 P Y PD - 3 1041 -010 (100P, R MG : M)Y PD U 6 1062 -008 (75- MG : NM)Y SD 75 mg + 3 0104-006 (75P MG : M)Y PD U 3 1106-007 (75P MG : M)Y PD U 2 1042 -005 (50P MG : NM)Y SD - 2 0101-004 (50- MG : M)- SD 50 mg - 3 1104-002P, (50 A MG : M)Y SD

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 Treatment Duration (Months) (1) Number of treatments reflect advanced or metastatic setting, not neo/adjuvant; also reflects combinations with targeted therapies CDK4/6, mTOR, PI3Ki 16 (2) P-palbociclib, A- abemaciclib, R-ribociclib, E-experimental treatment, could be placebo Summary of Oral SERD Competitor Clinical Benefit Rates

40% Clinical Benefit Rate in severe and heavily pre-treated patient population

60% GDC-9545 55% 50% 42% 40% 40% AZD9833 ZN-c5 SAR439859 30% 36%

20% 16%

Clinical Benefit Rate Benefit Clinical Fulvestrant 15% G1T48 10%

0% 0 1 2 3 4 5 Median Prior Number of Regimens More Severe Patient Population Sources: Fulvestrant BELLE-3 Publication; AZD9833 ASCO 2020 Presentation; GDC-9545 SABCS 2019 Poster; SAR439859 ASCO 2019 Poster; G1T48 ESMO 2019 Poster (1) Clinical Benefit Rate, various studies and lines of therapies (2) The data presents a non-head to head summary comparison. While we believe the comparison is useful in evaluating the observed interim results of ZN-c5 in the Phase 1/2 clinical trial, our Phase 1/2 clinical trial and the AZD9496, AZD9833, GDC-9545, SAR439859, LSZ102 and G1T48 clinical trials were separate trials conducted at different sites with other differences, including, for example, that the subjects in the GDC-9545 clinical trials had 1 median line of prior treatment while the subjects in our Phase 1/2 clinical trial had 4 median lines of prior treatment. In this regard, we have not conducted a head-to-head comparison of ZN-c5 and any of the presented oral SERDs in a clinical trial. Results of a head-to-head comparison may differ significantly from those set forth in the table. In addition, because our Phase 1/2 clinical trial and the AZD9496, AZD9833, GDC-9545, SAR439859, LSZ102 and G1T48 clinical trials were separate trials and because we have interim data for 15 patients in our Phase 1/2 clinical trial from the Phase 1, monotherapy dose 17 escalation portion as of June 30, 2020, differences between the results of our clinical trial and the AZD9496, AZD9833, GDC-9545, SAR439859, LSZ102 and G1T48 clinical trials may not be statistically or clinically meaningful. For these reasons, you should not place undue weight on the table. Summary of Potential Oral SERD Competitors

AZD9496 AZD9833 GDC-9545 SAR439859 LSZ102 G1T48 ZN-c5 (1) (AstraZeneca) (AstraZeneca) (Roche) (Sanofi) (Novartis) (G1 Therapeutics) (Zentalis)

600 mg BID 75 mg QD* 90 mg QD 1,000 mg QD Dose (10, 30 and 100 mg Taken 400 mg QD 600 mg QD (600 and 1,000 mg 100 mg (Maximal Feasible Dose) (Initial Reported Data) Forward) Taken Forward) AUC (ng*hr/mL) 8,676 683 12,200 ~36,600 (2) 25,600 2,690 106,000 Treatment-Related AEs: % Patients Treated with Drug (All Doses Tested) Diarrhea 36% 0-10% (3) 17% 8% 62% 27% 3% Nausea 22% 18% 21% 8% 56% 15% 10% Bradycardia N/A 45% 10% N/A N/A N/A 0% Visual Disturbances N/A 53% 0-10% (3) N/A N/A N/A 0% Other Notable Adverse Events: All Doses Tested

Hot Flush; Dizziness AST/ALT Increase; Other Notable QTcF DLT; Reported; Fatigue; Hot Flush; Full AE Tables on Hot Flush, Hot Flush N/A Dizziness Arthralgia; QTc Fatigue Following Page Adverse Events Fatigue Reported

Sources: AZD9496 Phase 1 Publication; AZD9833 ASCO 2020 Poster; GDC-9545 SABCS 2019 Poster; LSZ102 Poster SABCS 2017; SAR439859 ASCO 2020 Poster; G1T48 ESMO 2019 Poster (1) The data presents a non-head to head summary comparison. While we believe the comparison is useful in evaluating the observed results of ZN-c5 in the Phase 1/2 clinical trial, our Phase 1/2 clinical trial and the AZD9496, AZD9833, GDC- 9545, SAR439859, LSZ102 and G1T48 clinical trials were separate trials conducted at different sites with other differences, including, for example, that the subjects in the GDC-9545 clinical trials had 1 median line of prior treatment while the subjects in our Phase 1/2 clinical trial had 4 median lines of prior treatment. In this regard, we have not conducted a head-to-head comparison of ZN-c5 and any of the presented oral SERDs in a clinical trial. Results of a head-to-head comparison may differ significantly from those set forth in the table. In addition, because our Phase 1/2 clinical trial and the AZD9496, AZD9833, GDC-9545, SAR439859, LSZ102 and G1T48 clinical trials were separate trials and because we have interim data for 29 patients in our Phase 1/2 clinical trial from the Phase 1, monotherapy dose escalation portion as of June 30, 2020, differences between the results of our clinical trial and the AZD9496, AZD9833, GDC-9545, SAR439859, LSZ102 and G1T48 clinical trials may not be statistically or clinically meaningful. For these reasons, you should not place undue weight on the table. 18 (2) Visual estimation based on graph (3) Ranges represent adverse events where posters do not disclose events <10% ZN-c5: Well Tolerated as Monotherapy and in Combination with Palbociclib

Monotherapy Treatment-Related AEs* Combination Treatment-Related AEs**

*Based on first 29 patients from Phase 1 monotherapy dose escalation/expansion as of Jun 30, 2020 **Based on first 15 patients from Phase 1 Combination Dose Escalation as of June 30, 2020

19 ZN-c3: WEE1 Inhibitor

20 ZN-c3: Oral WEE1 Inhibitor for Solid Tumors

1 2 3 IDENTIFY: WEE1 ANALYZE: AZD1775 CREATE: ZN-c3 • Highly attractive DNA damage • Promising efficacy across tumor • Designed as an improved oral response target types (ovarian and pancreatic WEE1 inhibitor with respect to: • Active across multiple tumor cancer) − Solubility types with potential for • Potentially limited by narrow − Selectivity combination therapeutic window − PK properties • No approved WEE1 inhibitor • Goal: broader therapeutic and currently only a few in window development (i.e. AstraZeneca’s • Potential to have broad AZD1775) applicability as monotherapy and in combination

Current Status: Phase 1/2 Trial in Monotherapy Dose Escalation (22 Patients Dosed) and Phase 1 Combination Trial with Chemotherapy in Advanced Ovarian Cancer

21 Third-Party WEE1 Inhibitor Shows Strong Preclinical Activity and Clinical Responses

Combination of WEE1 and PARP Phase II Study of WEE1 Inhibitor AZD1775 Plus Phase II Trial of WEE1 Inhibitor in Inhibitors Showed Improved Anti- Carboplatin in Patients With TP53-Mutated recurrent Uterine Serous Tumor Activity as Compared to the Use Ovarian Cancer Refractory or Resistant to First- Carcinoma (USC) (3,4) of Each as Monotherapy (1) Line Therapy Within 3 Months (2)

AZD1775 AZD1775 AZD1775 AZD1775

(1) Fang, Y. Cancer Cell (2019. A total of 2 x 106 OVCAR8 were injected subcutaneously (s.c.) and grown for 2 weeks in nude mice. Mice were randomized with six in each group and treated as indicated. Average tumor volume ± SEM are displayed. p value: one-way ANOVA. **p < 0.01 (2) Leijen, R. Journal of Clinical Oncology (2016) 22 (3) Liu, J.F. AZD1775 SGO Presentation (2020) (4) An aggressive subtype of endometrial carcinoma characterized by frequent TP53 mutations (>90%) ZN-c3: More Selective for WEE1 in Kinase Screening Panel

AZD – 1775 (1) ZN-c3

% Inhibition (@ 1µM) 90+ 75-89

(1) AZD1775 data based on evaluation of comparable proxy chemical compound purchased from commercial sources rather than obtained from the pharmaceutical company developing the compound. 23 Illustrations reproduced courtesy of Cell Signaling Technology, Inc. (www.cellsignal.com) ZN-c3: Improved Tumor Concentration in Preclinical Models

Study ZN-c3 AZD1775 (A-427 NSCLC)

Dose 20 40 80 20 40 80 (mg/kg/day)

Cmax (ng/mL) 1,167 1,997 5,100 635 2,460 4,703

Tmax (hr) 1 1 1 1 1 1

. AUC0-24hr (ng hr/mL) 4,863 17,088 39,722 1,494 6,313 13,408

Tumor Conc. (ng/mL) 10.5 48.0 811 BQL BQL 6.95

Note: BQL: Below Quantifiable Level (1) AZD1775 data based on evaluation of comparable proxy chemical compound purchased from commercial sources rather than obtained from the pharmaceutical company developing the compound.

24 ZN-c3: Induced Prolonged Tumor Growth Delay at Intermittent Dosing

Lung Cancer Model (A-427) 3,500 Vehicle QD x 41

3,000

ZN-c3 120 mg/kg, (QD x 4, 3 days off) x 1 100 mg/kg, (QD x 4, 3 days off) x 4

) 2,500 3

2,000 AZD1775 120 mg/kg, (QD x 4, 3 days off) x 1 100 mg/kg, (QD x 4, 3 days off) x 5 (1)

1,500

Tumor Volume (mm Volume Tumor 1,000 67 days delay > 105 days delay

500

0 9 19 29 39 49 59 69 79 89 99 109 119 129 139 149 159 169

Dosing Period Days After Tumor Inoculation

(1) AZD1775 data based on evaluation of comparable proxy chemical compound purchased from commercial sources rather than obtained from the pharmaceutical company developing the compound. 25 ZN-c3: Clinical Development Plan

Ongoing and Planned Clinical Programs Overview

• Interim and preliminary Phase 1 Phase 2 safety results from Phase 1 monotherapy dose escalation (1) Solid Tumors: Monotherapy Dose Solid Tumors: Combination – Favorable PK profile Escalation Approaches (Chemo & PARPi) observed – No DLTs observed and well tolerated Uterine Serous Carcinoma: Ovarian Cancer: – Enrollment is ongoing; Chemo Combination Phase 1b Study Monotherapy Phase 2 Study expect to report topline data in 2021 Initiated 4Q 2020 Expected Initiation 2021

Two Additional Combination Studies (2) Expected Initiation 2021

(1) As of the June 19, 2020, in the Phase 1, monotherapy dose escalation portion of the ongoing ZN-c3-001 trial, a total of 22 patients were enrolled and dosed with data available in the electronic data 26 capture system, two patients each at the dose levels of 25 mg, 50 mg, 200 mg and 300 mg, four patients at 100 mg and ten patients at 75 mg/day (2) Phase 1 combination trials including with chemotherapy and PARP inhibitors in ovarian cancer and other targeted indications ZN-c3: Phase 2 Monotherapy Study in USC

Overview of Uterine Serous Carcinoma (USC) Represents High Unmet Medical Need

• Type II endometrial cancer Comprises 10% of Endometrial Cancers with Highest Mortality

• Not hormonally mediated All Endometrial Cancer • Approx. 70% of USC present with Stage III or IV disease at New Cases and Deaths (2020 Estimated) diagnosis 100% All Other • Poor survival rates; only 30-50% even if confined in uterus Endometrial Cancer 7,680 • >90% of USCs have TP53 mutation 59,058 50% • Recurrence rates are 29-80% post surgery • ~6k new cases and ~4.5k deaths in U.S. per year 4,910 • Current standard of care include: comprehensive surgery, 6,562 USC 0% adjuvant chemotherapy and adjuvant vaginal cuff New Cases Deaths brachytherapy

Will Initiate Phase 2 Monotherapy Trial for Patients with USC in 2021

Source: Gynecologic Oncology 115 (2009) 142-153, David Boruta et al.; National Cancer Institute, SEER 2020 Data. 27 ZN-c3: Well Tolerated Based on Initial Safety Data

AZD1775 AZD1775 ZN-c3 ZN-c3 ZN-c3 ZN-c3 ZN-c3 ZN-c3 225mg BID x 225mg BID x 25mg QD x 21/21 50mg QD x 21/21 75mg QD x 21/21 100mg QD x 21/21 200mg QD x 21/21 300mg QD x 21/21 1wk/21days 2wk/21days days days days days days days N = 3 N = 19 N = 2 N = 2 N = 10 N = 4 N = 2 N = 2 Cumulative dose/21 days 1,125 mg 2,250 mg 525 mg 1,050 mg 1,575 mg 2,100 mg 4,200 mg 6,300 mg Grade (MedDRA) 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 Gastrointestinal disorders Nausea 1 1 10 4 1 1 1 1 Vomiting 1 1 10 5 1 1 Diarrhoea 11 3 1 1 1 1 Abdominal 1 1 2 1 distension/bloating Abdominal Pain 4 1 Flatulence 3 Oral mucositis 1 1 Gastritis 1 Hematologic AEs Anemia 1 2 4 2 1 1 Leukopenia 1 1 1 4 4 1 1 Neutropenia 1 5 2 Thrombocytopenia 4 4 1 1 Investigations Increase in ALT 5 1 1 Increase in AST 3 2

ZN-c3-001 Data as of June 19, 2020 AZD1775: Do et al. JCO 2015 28 ZN-c3: Initial Safety Data in Hematological Parameters

No observed effects on hematological parameters for dose levels ranging from 25 mg/day up to 300 mg/day

Neutrophils (1) Platelets (1) Hemoglobin (1)

Eligibility Threshold (1.5) Eligibility Threshold (100)

Note: Each Line Represents An Individual Patient

(1) Data as of June 19, 2020; Dose levels <100 mg: no effect on ANC, platelets and Hgb 29 ZN-c3: Favorable Initial Pharmacokinetics Profile

Day 1 (1) Day 15 (1)

Cmax Tmax AUC0-8hr AUC0-24hr Cmax Tmax AUC0-8hr AUC0-24hr (ng/mL) (hr) (2) (ng*h/mL) (ng*h/mL) t½ (hr) (ng/mL) (hr) (2) (ng*h/mL) (ng*h/mL) t½ (hr)

25 mg 14 2 62 87 10 9 2 41 63 11

50 mg 55 2.5 246 533 8 48 4 255 594 15

75 mg 122 2 620 1,100 7 152 1 842 1,330 9

100 mg 124 1 822 1,120 8 199 3 822 1,620 9

200 mg 353 2 1,550 2,870 7 712 2 3,480 6,160 7

(1) 25 and 50 mg: n=2; 75 mg: n=10 on Day 1 and n=8 on Day 15; 100 mg: n=4; 200 mg: n=3 30 (2) Median are listed for Tmax ZN-c3: Favorable Initial Pharmacokinetics Profile (Cont’d)

ZN-c3: Day 1 (1) AZD1775: Day 1 (3)

Cmax Tmax AUC0-8hr AUC0-24hr Cmax Tmax AUC0-8hr (ng/mL) (hr) (2) (ng*h/mL) (ng*h/mL) t½ (hr) (ng/mL) (hr) (2) (ng*h/mL)

25 mg 14 2 62 87 10 25 mg 21*** 3 *** 100***

78* 2 * 371* 50 mg 55 2.5 246 533 8 50 mg 67*** 3 *** 329***

75 mg 122 2 620 1,100 7 75 mg 112** 1** 550** 104* 3* 570 * 100 mg 124 1 822 1,120 8 100 mg 162** 2** 720 ** 157*** 2*** 730 *** 236* 4* 1,260* 200 mg 353 2 1,550 2,870 7 200 mg 232** 3** 1,205** 239*** 3*** 1,165*** 25 and 50 mg: n=2; 75 mg: n=10; 100 mg: n=4; 200 mg: n=3 AZD1775 data based on Part 2A (100 mg, 200 mg) and Part 2B (25 mg, 50 mg, 75 mg) of Phase 1 AZD1775 combination study since data at above doses not available from monotherapy data: * With Cisplatin; ** With (3) (1) 25 and 50 mg: n=2; 75 mg: n=10 on Day 1 and n=8 on Day 15; 100 mg: n=4; 200 mg: n=3 Carboplatin; *** With Gemcitabine

(2) Median are listed for Tmax 31 (3) AZD1775 data from Leijen, et al (2016) J Clin Oncol 34:4371-4380) ZN-d5: BCL-2 Inhibitor

32 ZN-d5: Oral BCL-2 Inhibitor for Hematologic Malignancies

1 2 3 IDENTIFY: BCL-2 ANALYZE: Venetoclax CREATE: ZN-d5 • Broad applicability as anti- • Demonstrated clinical efficacy in • ZN-d5 designed as an oral BCL-2 apoptotic target hematologic malignancies inhibitor to optimize: • Difficult target given intracellular • Approvals in CLL/SLL and AML − Potency location • Addresses side effects of − Selectivity • Potential for use in combination previous BCL-2 inhibitors − PK properties • Venetoclax: only approved BCL- • Thrombocytopenia still observed • Plan to explore in combination 2 inhibitor in 29% of patients, attributed to with ZN-c5 for breast cancer BCL-xL inhibition • Small number of agents in development

Current Status: Phase 1 trial in AML and Non-Hodgkin’s Lymphoma

33 ZN-d5: Excellent In Vitro Potency and Better BCL-xL Selectivity

ZN-d5 has >14x improved selectivity for BCL-2 vs BCL-xL compared to venetoclax

CTG IC50 (nM) Affinity (nM) Compound ALL MCL DLBCL AML

BCL-2 BCL-xL RS4;11 Granta-519 DOHH-2 Toledo HL-60 Molm-13 MV4-11 Kd Kd

Venetoclax 0.41 28 2.9 161 43 191 26 18 3.8

ZN-d5 0.29 190 5.1 89 50 92 21 39 5.1

34 ZN-d5: Observed to Bind with Higher Affinity to BCL-2 Mutants than Venetoclax in In Vitro Assay Mutations in BCL-2 may be driving sub-clonal pockets of resistance to Venetoclax in CLL

CLL Progression on Venetoclax

IC50 (nM) BCL-2 Type Compound

WT G101V F104L D103Y

• 55% (16/29) patients acquired mutations in BCL2 family members Venetoclax 1.3 7.3 8.4 18.3 • 48% (14/29) with mutations in BCL2 • 21% (6/29) with mutations in PMAIP1 (NOXA), BAX or BAD

• Majority (9/14) were detected with BCL2 mutations after ZN-d5 1.4 3.7 1.4 5.0 24 months on venetoclax • 55 % (16/29) of patients with CLL progression Note: Competition assay for displacing BAK peptide bound to BCL-2 Source: Chyla, B. ASH Presentation (2019)

35 ZN-d5: Strong Anti-Tumor Activity Consistent with Venetoclax in Preclinical Leukemia Model

Xenograft Leukemia Model (RS4;11), Mean ± SE 2,400

VehicleVehicle

1,800

) 3 Venetoclax (50 Venetoclax (50 mg/kg)(1) p.o. qd Dosing Stop ×mg/kg) 11 QD x 11 1,200

ZN-d5ZN-d5 (50 (50mg/kg) mg/kg) p.o. qd × 11 QD x 11

Tumor Volume (mm Volume Tumor 600

0 21 24 27 30 33 36 39 42 45 Days After Tumor Inoculation

(1) Venetoclax data based on evaluation of comparable proxy chemical compound purchased from commercial sources rather than obtained from the pharmaceutical company developing the compound. 36 Initial Venetoclax + Tamoxifen Clinical Data is Compelling (Presented at 2018 SABCS)

37 Source: Lok, Sheau et al. Cancer Discovery March 2019 All Oral Internal Combination of ZN-c5 + ZN-d5 Shows Promising Potential in MCF7 Model

Breast Cancer Model (MCF7), Mean ± SE

700 Vehicle ZN-d5 200 mg/kg

600 ZN-c5 10 mg/kg

ZN-d5 200 mg/kg + ZN-c5 10 mg/kg ) 3 500

400

olume (mm olume V

300 Tumor Tumor

200

100

0 -1 3 7 11 15 19 23 Days Post Treatment

38 ZN-e4: EGFR Inhibitor

39 ZN-e4: Third-Generation EGFR Inhibitor for NSCLC

1 2 3 IDENTIFY: EGFR ANALYZE: Osimertinib CREATE: ZN-e4 • Regulator of proliferation and • Addresses the T790M-mediated • ZN-e4 designed to achieve similar survival in lung cancer acquired resistance and potency, but: improving efficacy • Third generation inhibitors − Improved selectivity for mutant targeting T790M mutation have • ~60% of patients reported EGFR produced clinically meaningful rashes − No production of potent benefits • AZ5104, a major metabolite of metabolite for wild-type EGFR osimertinib, may be − Better solubility • Osimertinib: only approved responsible for these toxicities third-generation EGFR inhibitor • Actively evaluating potential combinations • Broad combination potential

Current Status: Phase 1/2 Trial (Monotherapy Dose Escalation)

40 ZN-e4: Improved Selectivity and Tolerability in Preclinical Models

Favorable Tolerability Observed: ZN-e4 Similar ZN-e4 is More Selective than Osimertinib… Weight Loss to Osimertinib at 5x Efficacious Dose (1) Double Single Mutant Wild-Type EGFR Mutant Lung Cancer Model (NCI-H1975), Mean ± SE Mutant Cell Cell Cell 1,600

IC50 (nM) IC50 (nM) IC50 (nM) 1,200 Osimertinib: Core Drug 15 29 294 800 400

ZN-e4: Core Drug 20 38 839 0 Tumor Volume (mm³) Volume Tumor 0 5 10 15 20 25 …And Does Not Form a Potent Metabolite for 4% Study Days Wild-Type EGFR 2% 0% Double Single Mutant Wild-Type (2%) Mutant Cell Cell Cell (4%) IC (nM) IC (nM) IC (nM) 50 50 50 (6%)

Osimertinib: AZ5104 2 (2) 2 (2) 33 (2) (8%) % % Change, BW(%) (10%) No Potent Metabolite for Wild-Type EGFR ZN-e4 0 5 10 15 20 25 Formed Study Days Vehicle Osimertinib (10mg/kg) QDx14 ZN-e4 (10mg/kg) QDx14

(1) Osimertinib data based on evaluation of comparable proxy chemical compound purchased from ZN-e4 (25mg/kg) QDx14 ZN-e4 (50mg/kg) QDx14 commercial sources rather than obtained from the pharmaceutical company developing the compound. (2) Finlay, M.J. of Med. Chem. (2014) 41 ZN-e4: Clinical Development Overview

Focused on completion of Phase 1 trial and will evaluate whether to initiate Phase 2 portion of upon its completion

Interim & Preliminary Efficacy: Change In Target Lesion Size (1) Current Status 120 • As of Feb. 5, 2020, 19 patients had been 100 dosed in this trial in seven dose level 80 cohorts (2) 60 • 11 of 19 patients treated with

40 PD Threshold osimertinib

20 • 3 partial responses (2 confirmed, 1 %Change Baseline from - 0 unconfirmed) in osimertinib-naïve

(20) patients at 160, 320 and 480 mg

(40) • One other patient currently with stable PR Threshold (60) disease has a reduction in target lesion Target Lesion Size Size Lesion Target size of approximately 29%. (80) • Generally well tolerated, 1 DLT at the 320 (100) Baseline Wk 6 Wk 12 Wk 18 Wk 24 Wk 30 Wk 36 Wk 42 Wk 48 Wk 54 Wk 60 mg dose level; trial is currently ongoing at a higher dose level 480 mg 320 mg 240 mg 160 mg 80 mg 40 mg 20 mg

(1) Includes data for the 16 evaluable patients as of the February 5, 2020 database cutoff date 42 (2) As of February 5, 2020, of the enrolled patients, 6 are continuing treatment and 13 have discontinued treatment, nine of which were due to disease progression Conclusion

43 Key Milestones

Expected Expected Event Event Timing Timing ZN-c5 (Oral SERD) ZN-d5 (BCL-2 Inhibitor) Phase 1 topline results from monotherapy dose ◼ Achieved ✓ ✓ IND Clearance ◼ April ‘20 escalation study July ‘20 ✓ Initiate Phase 1 trial in AML and Non-Hodgkin’s Lymphoma ◼ Achieved Initiate Phase 1b combination study with abemaciclib ◼ Achieved ✓ 4Q ’20 b 4Q ‘20

◼ Phase 1 topline results from Window of Opportunity study ◼ 1H 2021 ZN-e4 (EGFR Inhibitor) ◼ Initial results from dose escalation study ◼ 2021 ◼ Initiate Phase 2 monotherapy study ◼ 1H 2021 ◼ Evaluate potential for use in combinations for treatment of ◼ 2021+ ◼ Initiate Phase 2 combination study with palbociclib ◼ 1H 2021 lung cancer A ◼ Initiate Phase 1b combination study with ZN-d5 ◼ 2021 Integrated Discovery Engine ◼ Initiate Phase 2/3 monotherapy in earlier-stage patients ◼ 2021 (1) ◼ Submit 5th IND ◼ 2021 ZN-c3 (WEE1 Inhibitor) Zentera ✓ Initiate Phase 1 combination dose escalation study ◼ Achieved b 4Q ‘20 ◼ Submit ZN-c5, ZN-c3, ZN-d5 INDs in China ◼ 2021

◼ Phase 1 initial results from dose escalation study in ◼ 2021 advanced solid tumors a

◼ Initiate Phase 2 monotherapy in uterine serous carcinoma ◼ 2021

◼ Initiate two additional Phase 1 combination studies ◼ 2021 (1) 44 (1) Additional details to be announced in 1H 2021 ✓Achievements Contact Us

Anthony Sun, M.D., Melissa Epperly, CEO and Chairman CFO [email protected] [email protected] (212) 433-3780 (215) 290-7271

Corporate Office Science Center 530 Seventh Ave 10835 Road to the Cure Suite 2201 Suite 205 New York, NY 10018 San Diego, CA 92121

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